As the information-oriented society becomes more advanced, technologies for security protection of information processing systems have been developed. For example, ID cards are conventionally used to control access to computer rooms. However, the cards can be missing or stolen at high probability. To prevent this, introduction of personal recognition systems is starting, in which the fingerprint or the like of each person is registered in advance, and the fingerprint unique to each person is collated when he/she accesses the room, instead of using the ID cards.
Such a personal recognition system sometimes passes, e.g., a replica of a registered fingerprint. Hence, the personal recognition system must also recognize that the object is a living body in addition to fingerprint collation.